The field of the invention is dialysis procedures, and the invention relates more particularly to dialysis procedures that are carried out in a tubular membrane immersed in a dialysis buffer solution within a container.
The process of dialysis is well known and involves the placing of a sample on one side of a semipermeable membrane and a solvent on the other side of the membrane. Solutes of a small size, which are small enough to pass through the wall of the dialysis membrane, will pass from the sample to the solvent, whereas the larger solutes, or macrosolutes, will not be capable of passing through the dialysis membrane and, thus, will remain in the sample. By such a process, microsolutes, such as salts, may be removed from a sample by dialysis.
Dialysis tubing has been used to carry out this operation and typically one end of the tubing is clamped with a clamp of the type shown in U.S. Pat. No. 3,874,042. This permits the easy filling of a length of tubing, and in the past, various means were used such as the placing of one or more marbles inside the tubing to weight one end thereof. The clamps of the type shown in U.S. Pat. No. 3,874,042 are typically fabricated from polypropylene and are lighter than the dialysis bath and, thus, tend to float therein. It is advantageous to maintain the tubing in a vertical manner, and a weighted clamp has been disclosed in applicant's above-referenced patent which causes the dialysis sack to float in a vertical position. In order to facilitate the dialysis processing, it is advantageous to agitate the dialysis buffer solution so that the liquid layer at the surface of the semipermeable membrane is frequently renewed. This increases the concentration gradient across the membrane and speeds the flow of solutes through the membrane.
In the past, this agitation has typically been carried out by placing a stirrer in the dialysis buffer solution, but with the use of a weighted clamp the stirrer can become entangled with the dialysis tubing.